Hollow core door



United States Patent Office 3,385,fi2 Patented May 28, 1968 3,385,002HGLLOW C(IRE [300R Edward G. Quinif, Farmington, Mich. Walled Lake DoorCo., 19335 Beech-Daily Road, Detroit, Mich. 48240) Filed Mar. 14, 1966,Ser. No. 534,199 1 Claim. (Cl. 49-601) ABSTRACT OF THE DISCLOSURE Thehollow core door of this invention comprises a border frame, a corewithin the frame, and outer panels secured to opposite sides of theframe and confining the core within the frame. The core is composed of aplurality of interconnected laths and is extended to a stressed positionwherein the laths move apart to form an open cellular structure.

This invention relates to a core type construction unit and hasparticular reference to a new and improved hollow core door. A dooraccording to the invention utilizes an extendable strengthening coreformed from a plural y of flexible laths or slats. In the collapsedposition prior to insertion within the door frame, the core laths lieflat against each other so that the core is compact and easily handled.When the core is extended and positioned Within the door frame, thelaths are flexed apart so as to form a tier of lenticularly shapedsupport cells within the door frame. A given lath may be fitted intovarious size door frames by suitably flexing the lath components so thatthe core fills the frame. The elastically stressed slats assure that thecore is properly and uniformly spaced within the frame. The sides of thelath core members and frame are secured to the side panels to completean integral strong and durable door having high resistance to warpage orother structural deformation.

Accordingly an object of the invention is to provide a new and improvedflush door.

Another object is to provide a fiush door having an improvedstrengthening core member.

A further object is to provide a novel cellular strengthening core foruse in a construction unit.

Other objects and features of the invention will become apparent as thedescription proceeds, especially when taken in conjunction with theaccompanying drawing illustrating a preferred embodiment of theinvention, wherein:

FIGURE 1 is a partially broken away perspective view of a flush doorconstructed according to the invention;

FIGURE 2 is a sectional view taken along line 2-2 of FIGURE 1; and

FIGURE 3 is a sectional view taken along line 33 of FIGURE 1.

A flush door according to the invention includes an integral frame madeup side frame members 12 and 14 and top and bottom frame members 16 and18. Mounting blocks 20 may be secured to the inside of the frame on sideframe members 12 and 14 to facilitate the mounting of latch means on thedoor. Side panels 22 and 24 are fitted on either side of the frame anddefine an interior space filled by cellular core 26.

The core is made up from a plurality of aligned elongate flexible lathsor lath members 28. Depending upon the type of door or construction unitin which the core is used, the laths 28 may be made of wood, plastic,metal or other suitable material. As shown in FIGURE 1, each lath 28 issecured .at 30 to both ends of one of the adjacent laths and is securedat 32 to the middle portion of the other adjacent lath so as to form thecore 26. The core 26 is usually assembled with the laths 28 lying flatupon each other. In this collapsed position the core 26 is relativelycompact for ease in handling and storage.

In the mass construction of cores 26 it may be desirable to form thecores 26 from sheets of lath material having an approapriate lath width.In this case the sheets are piled one upon another and pairs of adjacentsheets are secured together at the side edges thereof as an example,with glue or other fastening means. The outer central portions of suchpairs lying between the lateral edges thereof are also secured together.Individual cores are sliced from one end of the assembled sheets of lathmaterial.

In the assembly of a flush door 10 according to the invention, the frameis first formed and then a core 26 having an appropriate width isextended and fitted within the frame by attaching the top and bottomlaths to the top and bottom frame members 16 and 18. Extension of thecore 26 forms a tier of lenticularly shaped support cells running fromthe top to the bottom of the door frame. The elastic deformation of thelaths assures that the core 26 is uniformly and accurately positionedwithin the frame to provide a uniformly reinforced flush door 10. Theflexibility of the laths also assures that laths 34 are properly seatedon the ends of the blocks 20. A working clearance 36 is provided betweenthe ends of the laths 28 and the frame side walls 12 and 14 and block 20to facilitate insertion of the core 26 within the frame.

When the core is properly positioned within the frame, the door iscompleted by gluing or otherwise securing the side panels 22 and 24 tothe edges of the frame and core laths, thus forming a rigid one-piecehollow flush door.

The type of core disclosed herein is particularly advantageous for usein the manufacture of flush doors since a given core can be extended,within the limits defined by the flexibility of the laths 28, to fitwithin various sized .door frames. This flexibility in core utilityeliminates the necessity of providing a different core for each sizedoor frame. The Strength of the door is dependent upon the number ordensity of support cells in the core unit. The use of a core having alarge number of relatively closely spaced support cells results in astronger door'than when a core having a smaller number of cells is used.

The drawing discloses a flush type door with a strengthening core 26having horizontally oriented support cells extending across the width ofthe door. It is sometimes desirable to use a strengthening core havingvertically extending support cells running from the top to the bottom ofthe door interior. When using such a core it is preferable to provide atleast three support cells in the core in order to assure properstrengthening of the door.

It should be noted that while the invention has been described in termsof a hollow flush door construction, it is obvious that the coredescribed herein may be used in any of a variety of construction unitswherein it is desirable to strengthen the unit by means of a coremember.

What I claim as my invention is:

1. A hollow core door comprising an elongated rectangular border frame,mounting blocks secured to the inner edges of the sides of said frameintermediate the ends of the latter in opposed relation to one another,a core composed of a plurality of elongated, thin generally parallelflexible laths oriented in side-by-side relation at right angles to areference plane, each lath being secured to two immediately adjacentlaths with the ends thereof secured in surface-to-surface relation tothe ends of one of said adjacent laths and the center thereof secured insurface-to-surface relation to the center of the other of said adjacentlaths, said core being extended from a relaxed position wherein the lahs lie fiat against each other to a stressed position. wherein the lathsare moved apart to form a tier of lenticular support cells, each cellbeing defined by one lath and said one adjacent lath, sa d stressed corebeing disposed in the plane and occupying the interior of said framewith said tier running between opposed ends of said frame and said lathsextending laterally between the sides of said frame, the ends of saidlaths above and below said blocks terminating closely adjacent the inneredges of the sides of said frame, the ends of the laths immediatelyabove and below said blocks being flexibly seated on the ends of saidblocks, the ends of said laths extending between said blocks terminatingclosely adjacent the inner edges of said blocks, and the uppermost andlowermost laths being centrally secured to the inner edges of the upperand lower ends respectively of said frame, and outer panels abutting andsecured to opposite sides of said frame and to opposite edges of saidlaths.

References Cited UNITED STATES PATENTS KENNETH DOWNEY, Primary Examiner.

